The Moderators, pictured at the 2013 Colorado Symphony Ball, are making a return appearance on Saturday. (Photo Provided by the CSO)

The Colorado Symphony Ball is all about music. Perhaps not the music one might expect, though.

For the second year, the gala will have a rock ‘n’ roll theme — From Bach to Rock — but it won’t be a total repeat of 2013, when The Moderators shared the stage with CSO musicians.

This year is billed as a battle of the bands in which The Moderators and the symphony will be joined by the DaVita Blues All Stars.

Which makes sense, considering how the event is being chaired by DaVita‘s CEO, Kent Thiry, and his wife, Denise O’Leary. And we have it on good authority that Thiry will take a turn at the mic. What he will sing was not revealed, but we have a feeling it will be worth the price of admission.

The set list is going to include classics of another genre: tunes that date back to the golden age of rock ‘n’ roll. Stuff by the Beatles, the Stones, Santana and Green Day.

“From Bach … To Rock” is the theme for the May 4 fundraiser being held in Denver’s historic rock palace, the Fillmore Auditorium and Denver’s favorite rock ‘n’ roll cover band, The Moderators, will be teaming up with symphony musicians to play everything from the classics to the contemporary … and a few things in between.

“This is a huge undertaking in that The Moderators never had to have orchestral charts created for their music before and we are creating them from scratch,” explains Sandy Lasky, the symphony’s senior communications adviser. “You know, so that their guitar is synced with our violins and their drummer is in time with our basses. The orchestra will also be playing a set of dance music following the joint performance.

“I remember years ago when we had to do the same thing with the Moody Blues prior to performing with them up at Red Rocks. It’s an amazing process.”